高速公路软土地基处理方法比较分析

Comparision and Analysis on Treatment of Highway Soft Soil Foundation

在软土地基上修建高速公路,主要问题是地基强度低,路堤沉降量大,沉降不均,路堤易失稳。采用数值方法对塑料排水板、碎石桩和刚性桩三种方法处理软土地基效果进行了比较分析,研究结果表明:①由于刚性桩的刚度远大于桩间土的刚度,因此承担了大部分路堤荷载,仅有小部分路堤荷载由桩间土承担,刚性桩能很好地控制软土地基的沉降,碎石桩能提高软土地基的承载力、改善软土的渗透性,处理效果差于刚性桩,塑料排水板仅能提高软土的渗透性,因此处理效果最差;②采用塑料排水板处理软土地基时,路堤最易发生失稳破坏,碎石桩次之,采用刚性桩处理软土地基时,路堤稳定性最高。

The main difficult of highway construction on soft soil foundation is easy instability of subgrade due to low strength of foundation,large and uneven settlement of embankment.The effects of three treatments for soft soil foundation,including plastic drainage plate,gravel pile and rigid pile,are compared and analyzed by numerical method.The results show：①Rigid pile can bear most of embankment load because its rigidity is far more than that of soil among the piles and only a fraction of embankment load is born by the soil among the piles.Hence rigid pile can control the settlement of soft soil foundation well.Gravel pile can increase the bearing capacity of this foundation and improve the permeability of soft soil,which has effect worse than rigid pile.Plastic drainage plate only can increase the permeability of soft soil,which has worst treatment effect;②Where plastic drainage plate is used for soft soil foundation treatment,it is most possible to occur embankment instability and gravel pile is the second.Where rigid pile is used for the same purpose,the embankment stability is highest.